Essential Efforts to Elevate Endurance, Part 2

In Part I of this series, we discussed how hard to do your long runs while training for a marathon. In this column, we will look at how long is far enough, how quickly to increase the distance of your long runs, and how many long runs to do in marathon preparation.

As a marathoner, your objective is to prepare optimally to run 26.2 miles, which includes reaching the starting line (and finish line) healthy. Common sense tells us that there is a tradeoff between running far enough to prepare physiologically for the marathon and remaining injury-free. The probability of injury tends to increase markedly as runs go beyond 20 miles, because when your muscles are highly fatigued, they lose their ability to absorb impact forces, which increases your risk of muscle strains, tendinitis, and even stress fractures. Towards the end of long runs, running technique tends to deteriorate, which can further increase the likelihood of injury. The risk of injury also increases if you do too many long runs, particularly if you have substantially increased the distance of your long runs during your marathon preparation.

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How far and how many?

How far your long runs should be, and how many of them you should do, depends on your marathoning experience, injury history and goals for the marathon. The more experienced you are, the more long runs you should be able to handle. On the other hand, the more injuries you have endured, the fewer long runs your body is likely to be able to deal with before breaking down. Depending on your goals, you may be willing to take greater risks during training or prefer to err on the side of caution.

The "long run prescription" table provides guidelines for the number and distance of long runs for marathoners with varying goals and injury histories. Admittedly, every marathoner is an experiment of one, so these recommendations will not work for everyone, but they are appropriate for most marathon runners.

For the majority of runners seeking a personal best, four to six long runs are sufficient. For those of you who are blessed with excellent biomechanics, a few more long runs over 20 miles will likely marginally improve your marathon performance. Seven to nine long runs in the 20 to 22 mile range will provide incremental physiological adaptations and provide even greater confidence for the last 6.2 miles. Finally, if you are an experienced marathoner who is intent on doing everything you can to ensure you achieve a personal best (and you are not injury-prone), then 10 to 12 long runs of at least 20 miles is the ultimate preparation. Of those, most should remain in the 20 to 22 mile range, with one or two runs of 24 miles. Doing more than this may look good in your training diary, but is likely to hinder, rather than improve, your marathon performance.

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How quickly should you increase your long runs?

A method that works well for many runners is to increase your long run by one mile per week, skipping every third week. If your current long run is 14 miles, then you would build up to 20 miles over eight weeks. In this example, your long run schedule would be: week 1: 15 miles, week 2: 16 miles, week 3: shorter long run, week 4: 17 miles, week 5: 18 miles, week 6: shorter long run, week 7: 19 miles, week 8: 20 miles. This rate of increase creates an appropriate balance between lengthening of your long run fairly quickly while giving your body time to adapt positively to the increased training load.

When should marathoners get serious about long runs?

There is no reason to do very long runs year-round. The "long run prescription" table provides recommendations for when to schedule your first 20 miler, based on the number of 20+ mile runs you will do. For novice marathoners, the first should be done five weeks pre-marathon, and the second two weeks later. For many experienced marathoners, the most effective pattern is to do two consecutive weeks with a run of 20+ miles, with a shorter long run every third week. This pattern also works well for fitting in pre-marathon tune-up races. Avoid getting into a routine of doing a very long run week-after-week because you will become too tired to do your other important training sessions such as tempo runs.

Your last run of 20 miles should generally be three weeks before your marathon, followed by a well-earned taper.

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